The present disclosure relates to an apparatus for driving a motor and a controlling method thereof.
In a switched reluctance motor (hereinafter, referred to as a SRM), which is a motor having a form in which it has a switching control apparatus coupled thereto, both of a stator and a rotor have a salient pole type structure.
Particularly, since only a stator part has a winding wound therearound and a rotor part does not include any type winding or permanent magnet, a structure of the SRM is simple.
Due to this structural feature, the SRM has a significant advantage in terms of manufacturing and production, and has good start-up characteristics and a large torque, similar to a direct current motor. In addition, the SRM requires less maintenance and has excellent characteristics in terms of a torque per unit volume, efficiency, rating of a converter, and the like, such that the use of the SRM has gradually increased in various fields.
The SRM as described above may have various types such as a single-phase, a two-phase, a three-phase, and the like. Among others, the two-phase SRM has a driving circuit simpler than that of the three-phase SRM, such that it has been significantly prominent in applications such as a fan, a blower, a compressor, and the like.
Further, in a switching apparatus of the two-phase SRM, various schemes have been suggested and used in order to control a current of a stator winding in a single direction. As one of the suggested schemes, there is a switching apparatus using an asymmetric bridge converter for driving an existing alternate current motor.
Further, the asymmetric bridge converter is most excellent in terms of variety of a control among converters for driving the SRM, and may independently control currents of each phase to enable currents of two phases to be overlapped with each other, such that it is appropriate for a high voltage and a high capacity and has a relatively low rating voltage of a switch.
In addition, the SRM does not include a coil wound around the rotor or a magnet attached to the rotor unlike other motors, such that it may have a small inertial moment and a high speed. However, position information of the rotor is required in order to start up the motor, and a method of using a separate sensor or a method of estimating the position information without using the sensor should be applied in order to obtain the position information.